A stereo telepresence system uses cameras to capture stereo images of one set of (one or more) remote participants, which are then displayed on 3D display devices of another set of (one or more) remote participants, and vice-versa. The general idea is to make the other participants look as if they are physically present on the opposite side of a room, e.g., as if the display device was a transparent window.
Existing stereo telepresence systems do not provide a particularly comfortable or realistic experience. A general problem is that when the geometric projections are correct, the focus depth cue is incorrect, in that the viewer (the subject) focuses at the depth of the screen (where the light is being emitted), rather than at the perceived depths of the object or objects being viewed.
While this simplifies the engineering of the display, it contributes to two viewing problems. For one, display surface are often closer to the subject than the (apparent) distances to the objects. Viewers are known to experience physical discomfort when they focus their eyes to a distance that differs significantly from their fixation distance, that is, the distance from the viewer to the intersection of their lines of sight/the point at which the eyes converge. Because the subject generally fixates on an object, and objects are typically located beyond the “transparent window,” the focus distance is typically significantly smaller than the fixation distance, which tends to result in physical discomfort.
Further, subjects in telepresence situations are known to be sensitive to encroachment, which refers to the sense that an object (generally another person) has moved too close for comfortable interaction. Because subjects estimate the distance to an object by (sub-consciously) weighing available cues to depth, the too-close focus distance biases their estimation downward, which can result in an unwarranted sense of encroachment.